Seed delivery apparatus, systems, and methods

ABSTRACT

A seed delivery apparatus and methods in which a seed conveyor delivers seed from a metering device to a trench in a controlled manner to maintain seed placement accuracy within the trench.

BACKGROUND

In recent years, the agricultural industry has recognized the need toperform planting operations more quickly due to the limited time duringwhich such planting operations are agronomically preferable or (in somegrowing seasons) even possible due to inclement weather. However,drawing a planting implement through the field at faster speedsincreases the speed of deposited seeds relative to the ground, causingseeds to roll and bounce upon landing in the trench and resulting ininconsistent plant spacing. The adverse agronomic effects of poor seedplacement and inconsistent plant spacing are well known in the art.

As such, there is a need for apparatus, systems and methods ofeffectively delivering seed to the trench while maintaining seedplacement accuracy at both low and high implement speeds.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation view of a prior art row unit of anagricultural row crop planter.

FIG. 2 is a side elevation view of an embodiment of a seed conveyor incooperation with a seed disc.

FIG. 3 is a partial side elevation view of an embodiment of a seedconveyor in cooperation with a seed disc.

FIG. 4 is a partial side elevation view of an embodiment of a seedconveyor depositing seeds in a seed trench.

FIG. 5 is a schematic illustration of an embodiment of a seed conveyorcontrol system.

FIG. 6 illustrates an embodiment of a seed conveyor control system.

FIG. 7 illustrates an embodiment of a process for controlling a seedconveyor.

FIG. 8 is a side elevation view of an embodiment of a planter row unitin cooperation with an embodiment of a seed conveyor.

FIG. 9 is a side elevation view of another embodiment of a seedconveyor.

FIG. 10 is a perspective view of the seed conveyor of FIG. 9.

FIG. 11 is a perspective view of an embodiment of a pulley.

FIG. 12 is a side elevation view of the pulley of FIG. 11.

FIG. 13 is a front elevation view of the pulley of FIG. 11.

FIG. 14 is a side elevation view of another embodiment of a seedconveyor showing an alternative embodiment loading wheel with sinusoidalfingers.

FIG. 15 is a perspective view of the loading wheel with sinusoidalfingers of FIG. 14.

FIG. 16 is an elevation view of an embodiment of a seed sensor.

DESCRIPTION

Referring now to the drawings, wherein like reference numerals designateidentical or corresponding parts throughout the several views, FIG. 1illustrates a side elevation view of a single row unit 10 of aconventional row crop planter such as the type disclosed in U.S. Pat.No. 7,438,006, the disclosure of which is hereby incorporated herein inits entirety by reference. As is well known in the art, the row units 10are mounted in spaced relation along the length of a transverse toolbar12 by a parallel linkage 14, comprised of upper and lower parallel arms16, 18 pivotally mounted at their forward ends to the transverse toolbar12 and at their rearward end to the row unit frame 20. The parallellinkage 14 permits each row unit 10 to move vertically independently ofthe toolbar 12 and the other spaced row units in order to accommodatechanges in terrain or rocks or other obstructions encountered by the rowunit as the planter is drawn through the field.

The row unit frame 20 operably supports a seed hopper 23, which may beadapted to receive seed from a bulk hopper (not shown), a seed meter 26,and a seed tube 28, as well as a seed trench or seed furrow openerassembly 30, and trench or furrow closing assembly 40. The trench openerassembly 30 comprises a pair of trench opener discs 32 and a pair ofgauge wheels 34. The gauge wheels 34 are pivotally secured to the rowunit frame 20 by gauge wheel arms 36. A coil spring 49 is disposedbetween the parallel arms 16, 18 to provide supplemental downforce toensure that the trench opener discs 32 fully penetrate the soil to thedesired depth as set by a depth adjusting member (not shown) and toprovide soil compaction for proper trench formation. Rather than a coilspring, supplemental downforce may be provided by actuators or othersuitable means such as disclosed in U.S. Pat. No. 6,389,999 to Duello,the entire disclosure of which is hereby incorporated herein byreference.

In operation, as the row unit 10 is lowered to the planting position,the opener discs 32 penetrate into the soil. At the same time, the soilforces the gauge wheels 34 to pivot upwardly until the gauge wheel arms36 abut or come into contact with the stop position previously set withthe trench depth adjusting member (not shown) or until a static loadbalance is achieved between the vertical load of the row unit and thereaction of the soil. As the planter is drawn forwardly in the directionindicated by arrow 39, the trench opener discs cut a V-shaped trench orfurrow 60 into the soil while the gauge wheels 34 compact the soil toaid in formation of the V-shaped trench. Individual seeds 62 from theseed hopper 23 are dispensed by the seed meter 26 into an upper openingin the seed tube 28 in uniformly spaced increments. As seeds 62 fallthrough the seed tube 28, the seeds move downwardly and rearwardlybetween the trench opener discs 32 and into the bottom of the V-shapedtrench 60. The trench 60 is then covered with soil and lightly compactedby the trench closing assembly 40.

It should be appreciated that because seeds 62 fall freely through theseed tube 28 in the row unit 10 described above, the path of travel ofthe seeds and the velocity of the seeds at the exit of the seed tube arerelatively unconstrained. It would be preferable to constrain the pathof travel of seeds 62 in order to reduce errors in spacing betweenseeds; i.e., placing seeds in the field at non-uniform spacing.Additionally, it would be preferable to control the velocity of seeds 62such that the seeds have a decreased horizontal velocity relative to theground upon landing in the trench 60.

A seed conveyor 100 is illustrated in FIG. 2. The seed conveyor 100includes a belt 140 disposed around upper and lower pulleys 152,154 andpreferably driven by the upper pulley 152; in other embodiments the seedconveyor may be driven by the lower pulley 154. The belt 140 includesflights 142. The seed conveyor 100 additionally includes a guide surface110 disposed adjacent to the flights 142 on one side of the seedconveyor. The seed conveyor 100 preferably includes a backing plate 130disposed to maintain the position of belt 140.

In operation, the seed conveyor 100 receives seeds 62 from a seed disc51 and conveys them to an exit 164. The seed disc 51 is preferablyhoused in a seed meter 26 similar to that illustrated in FIG. 1 androtates in a direction indicated by arrow 56 about a shaft 54 rotatablymounted in the seed meter. Turning to FIG. 3, the seed meter 26 ispreferably of the vacuum type as is known in the art, such that a vacuumsource (not shown) creates a vacuum behind the seed disc 51 (as viewedin FIG. 3), thus creating a pressure differential across apertures 52 inthe disc. As the apertures 52 rotate past a pool of seeds in thelocation generally indicated by reference numeral 58, the pressuredifferential causes individual seeds 62 to become entrained on eachaperture 52 such that the seeds are carried by the disc as illustrated.As the apertures cross a boundary such as axis 196, preferably atapproximately the 3 o'clock position of the seed disc 51, the vacuumsource is substantially cut off (e.g., by termination of a vacuum sealas is known in the art) such that the seeds 62 are released from thedisc as they cross axis 196. Seeds 62 preferably fall from the disc in asubstantially vertical fashion along an axis 192. Guide surface 110includes an angled portion 112, along which each seed 62 slides downwardand rearward before passing between two flights 142 at a seed inletgenerally indicated by reference numeral 162. Each seed 62 is thenconveyed downward by seed conveyor 100.

The belt 142 is preferably driven at a speed proportional to thegroundspeed of the row unit 10 designated by reference “St” (FIG. 4).For example, in some embodiments the seed conveyor 100 is driven suchthat the linear speed of belt 142 at the bottom of the lower pulley 154is approximately equal to the groundspeed St.

As illustrated in FIG. 3, each seed 62 is initially accelerated downwardby the flight 142 above the seed. Turning to FIG. 4, as each seed 62moves downward along the seed conveyor 100, it may fall away from theflight 142 above it. However, as each seed 62 nears the bottom of theseed conveyor, the flights 142 accelerate in order to travel aroundlower pulley 154 such that the flights 142 contact the seed and impart arearward horizontal velocity to the seed. Additionally, an angledportion 114 of the guide surface 110 guides the seed rearward, impartinga rearward horizontal velocity to the seed. Thus, as the seed 62 exitsthe seed conveyor at a seed exit generally indicated by referencenumeral 164, the seed has a downward vertical velocity component Vy anda horizontal velocity component Vx, the magnitude of which is less thanthe speed of travel St of the row unit 10. It should be appreciated thata smaller horizontal velocity component Vx is preferable because theseed 62 will experience less fore-aft roll as it lands in the trench 60,leading to more uniform seed placement. The angled portion 114preferably is disposed 20 degrees below horizontal.

Returning to FIG. 3, it should be appreciated that flights 142 travelfaster as they travel around the upper end of upper pulley 152, e.g.,above an axis 194. Additionally, the flights 142 have a substantialhorizontal velocity component above axis 194. As a result, attempting tointroduce seeds 62 between the flights above axis 194 may result inseeds being knocked away from the belt 140. Thus, the seed inlet 162 atwhich seeds 62 pass between flights 142 is preferably below the axis194. This result is preferably accomplished by positioning of the axis196 at which seeds are released from the disc 51 below the axis 194and/or by configuring angled portion 112 of guide surface such thatseeds 62 slide below axis 194 before entering the inlet 162.

Turning to the embodiment of FIG. 8, a seed conveyor 100 is illustratedin cooperation with a row unit 10. The row unit 10 includes a shankportion 35. The seed conveyor 100 is mounted to the shank portion 35 byattachment ears 106,108.

Conveyor Control Systems and Methods

A control system 1000 for controlling and monitoring the seed conveyor100 as well as any other seed conveyor embodiment disclosed herein isillustrated schematically in FIG. 5. The control system 1000 includes aplanter monitor 1005. The planter monitor 1005 preferably includes a CPUand user interface, and may comprise a monitor such as that disclosed inApplicant's U.S. Pat. No. 8,078,367. The planter monitor 1005 ispreferably in electrical communication with a seed conveyor motor 1020.The seed conveyor motor 1020 is operably coupled to the seed conveyor100 to drive the seed conveyor. For example, in some embodiments theseed conveyor motor 1020 includes a driven output shaft mechanicallycoupled to a central shaft of the upper pulley 154 or the lower pulley152. The seed conveyor 1020 preferably includes an encoder (e.g., ahall-effect sensor) for sensing the rotational speed of the conveyor100. The planter monitor 1005 is preferably in electrical communicationwith a meter drive motor 27. The meter drive motor 27 may comprise anyapparatus known in the art for driving seed meters at a desired speedsuch as a hydraulic drive or electric drive. As an example, the meterdrive motor 27 may comprise an electric motor mounted on or near theseed meter 26, the electric motor having an output shaft operablycoupled to the shaft 54 of the seed meter; in such an embodiment, themeter drive motor 27 preferably includes an encoder (e.g., a hall-effectsensor) for sensing the rotational speed of meter 50. The plantermonitor 1005 is also preferably in electrical communication with a speedsource 1010. The speed source may comprise a GPS system, a radar speedsensor, or a wheel speed sensor. The planter monitor may choose betweenmultiple speed sources by predicting reliability as disclosed inApplicant's International Patent Publication No. WO2012/015,957,incorporated herein in its entirety by reference.

Continuing to refer to FIG. 5, the planter monitor is preferably inelectrical communication with one or more seed sensors adapted formounting to the seed conveyor 100. The seed sensors may comprise one ormore seed sensors. The seed sensors may also be in electricalcommunication with the meter drive motor 27 and the seed conveyor motor1020.

FIG. 16 shows an embodiment of a seed sensor 1600 comprising a pluralityof transmitters 1610-1, 1610-2, and 1610-3 transmitting to an associatedplurality of receivers 1620-1, 1620-2, and 1620-3. To determine whetherthere is a seed 62 in seed aperture 52, the signals received at theplurality of receivers can be averaged. Alternatively, the percenttransmittance between each pair of transmitter and receiver can bemeasured and then weighted based on the percent transmittance and thenthe weighted results can be averaged. This can be useful when a seed isoriented in seed aperture 52 such that the seed 62 does not obstruct allof the plurality of transmitters 1610-1, 1610-2, and 1610-3 andreceivers 1620-1, 1620-2, and 1620-3 at the same time. Having aplurality of sensors allows for better determination of whether there isa seed 62 in seed aperture 52.

Turning to FIG. 6, one embodiment of a planter monitor control system1000 is illustrated. The planter monitor control system 1000 of FIG. 6includes a seed sensor 550 mounted to the sidewalls of the seed conveyor100. The meter drive motor 27 in the planter monitor control system 1000of FIG. 6 comprises an electric drive. The speed St of seed conveyor 100is generally to the left along the perspective of FIG. 6 and has amagnitude which varies with the speed and direction of the plantingimplement.

A process 1100 for controlling the rotational speed of the seed conveyor100 is illustrated in FIG. 7. At block 1102 the planter monitor 1005obtains a speed of the planting implement from the speed source 1010. Atblock 1103, the planter monitor 1005 preferably obtains the currentcommanded planting population (i.e., the number of desired seeds plantedper acre) from a memory contained within the planter monitor 1005. Atblock 1105, the planter monitor 1005 preferably commands a rotationalspeed of meter 50 based on the desired population and the currentimplement speed.

Continuing to refer to FIG. 7, at block 1110, the planter monitor 1005preferably determines an operating speed of the seed conveyor 100. Thisstep may be accomplished using a Hall-effect or other sensor adapted tomeasure the driving speed of the electric motor or the rotational speedof the driven shaft of the seed conveyor 100. This step may also beaccomplished by measuring the time between flights 142 passing the seedsensor 550. It should be appreciated in light of the instant disclosurethat step of block 1110 does not require measuring an actual operationalspeed but may comprise measuring a criterion related to the operationalspeed.

Continuing to refer to FIG. 7, at block 1500 the planter monitor 1005preferably determines the ground speed St of the seed conveyor 100. Insome embodiments, this step may be accomplished by assuming that thetractor or implement speed reported by the speed source 1010 is equal tothe ground speed St of the seed conveyor 100. Such a method is accuratewhen the tractor and toolbar 12 are not turning, but becomes inaccuratewhen the tractor and toolbar 12 are turning. In other embodiments thestep of block 1500 may be performed more accurately by determining thelocal ground speed St of each conveyor 100 along the toolbar 12. Suchembodiments are described herein in the section entitled “ConveyorGround Speed Determination.”

Continuing to refer to FIG. 7 and process 1100, at block 1117 theplanter monitor 1005 preferably determines a conveyor motor speedcommand, e.g., using a calibration curve. The calibration curvepreferably relates the ground speed St to a desired operational speedSo. It should be appreciated in light of the instant disclosure that thecalibration curve could also relate a criterion related to ground speed(such as a measured voltage or commanded voltage) to a criterion relatedto a desired conveyor speed (such as a measured voltage or commandedvoltage).

Continuing to refer to FIG. 7 and the process 1100, at block 1120 theplanter monitor 1005 preferably commands the new desired conveyor speed.It should be appreciated in light of the instant disclosure that thechange in conveyor speed command may be deferred until the actualconveyor speed is outside of a preferred range, e.g. 5%, with respect tothe desired conveyor speed.

Turning to FIGS. 9-10, another embodiment of a seed conveyor assembly900 is illustrated. As with the loading conveyor embodiments disclosedin Applicant's International Patent Publication No. WO2013/049198,hereby incorporated by reference herein in its entirety, loading wheels910, 920 are driven in opposing directions in order to grasp seeds fromthe seed disc of the seed meter and eject the seeds between flights 932of a conveyor 930 (e.g., an endless conveyor) housed within a housing980. In the illustrated embodiment, the conveyor 930 comprises aflighted belt as illustrated in FIGS. 9-10. In other embodiments, theconveyor 930 may comprise other structure suited to convey seeds from anupper to lower position such as a brush belt having a plurality ofbristles for receiving seeds.

FIGS. 9 and 10 likewise illustrate an upper pulley 950 about which theconveyor 930 is driven in operation. A cleaning strip 970 is preferablydisposed adjacent (e.g., directly axially adjacent) to the upper pulley950. The cleaning strip 970 preferably extends radially outwardly fromthe pulley 950. The cleaning strip 970 is preferably arcuate. Thecleaning strip 970 preferably extends arcuately forwardly along thedirection of rotation of the pulley 950 (e.g., counter-clockwise on theview of FIG. 9). An upper end of the cleaning strip 970 is preferablyadjacent to a radially outer surface of a hub portion 959 (FIG. 11) ofthe pulley 950. In operation, mud or other debris is preferably scrapedfrom the pulley 950 by contact with the cleaning strip 970 as the pulleyrotates adjacent to the cleaning strip 970.

Continuing to refer to FIGS. 9-10, an agitation strip 960 isillustrated. The agitation strip 960 is preferably substantiallyparallel with (and preferably substantially flush with) an interior wall982 of the housing 980. The agitation strip 960 preferably includes aplurality of agitation elements 962 which may be arranged in rows 964(e.g., diagonally-oriented rows as illustrated in FIG. 10). Theagitation strip 960 is preferably disposed adjacent to a portion of theconveyor 930 in which seeds are conveyed, e.g., between an entry pointat which seeds are introduced by the loading wheels 910, 920 and arelease point at which seeds are released from the conveyor into aplanting trench. The agitation strip 960 is preferably disposed adjacentto a portion of the conveyor 930 in which seeds are conveyed prior tobeing sensed by a seed sensor, e.g., between the entry point at whichseeds are introduced by the loading wheels 910, 920 and a sensing pointat which seeds are detected by a seed sensor. The agitation elements 962preferably extend toward the conveyor 930. A distal end of eachagitation element 962 is preferably directly adjacent to a distal end ofthe passing flights 932.

In operation, a seed may occasionally become trapped between the distalend of a flight 932 and an interior wall 982 of the housing 980 afterbeing introduced into the conveyor 930. As the trapped seed is draggedalong the interior wall 982, the trapped seed is preferably moved towardand across the surface of the agitation strip 960. Upon making contactwith the agitation elements of the agitation strip 960, the trapped seedis preferably agitated (e.g., vibrated, moved) and dislocated frombetween the flight 932 and the interior wall 982. After being dislocatedfrom between the flight and the interior wall, a partially verticallyupward force between the seed and one or more agitation elementspreferably urges the seed into one of the flight gaps 933 between theflights of the conveyor 930, preferably the flight gap directlyvertically above the flight that had trapped the seed.

The agitation strip 960 preferably comprises an elastic material (e.g.,rubber, polyurethane). The agitation strip 960 is preferably removable,preferably without the use of tools. The agitation strip 960 may bereplaced with a one of a plurality of replacement agitation strips. Eachreplacement agitation strip may differ from the other replacementagitation strips in one or more of the following criteria: (1) agitationelement height, (2) agitation element shape, (3) agitation elementnumber, (4) configuration (e.g., pattern) of agitation elements, or (5)material type or properties (e.g., elasticity).

Referring to FIGS. 9-10, a seed guide 940 is illustrated having a reliefportion 942 and an introduction portion 944. The relief portion 942 ispreferably disposed radially farther from the pulley 950 (and preferablyfarther from the conveyor 930) than the introduction portion 944. Therelief portion 942 is preferably arcuate, and preferably extendsarcuately along a path substantially parallel to the path of a flight932 passing the relief portion in operation of the conveyor 930. Inoperation, seeds may slide along the relief portion 942 beforecontacting the introduction portion 944. Upon contacting theintroduction portion 944, the seed is preferably translated (e.g.,bumped, urged, forced) in a direction toward the conveyor 930 and ispreferably introduced into a flight gap 933 by contact with theintroduction portion 944.

Referring to FIGS. 9-13, an improved upper pulley 950 is illustrated incooperation with the conveyor 930 for driving the conveyor in operation.The pulley 950 preferably includes a first set of radially arrangedpulley teeth 952-1 and a second set of radially arranged pulley teeth952-2. The pulley teeth 952-1 are preferably separated by a pitch angleB (e.g., 60 degrees). The pulley teeth 952-2 are preferably separated bythe same pitch angle B (e.g., 60 degrees). The first set of drive teeth952-1 and the second set of drive teeth 952-2 are preferably offset fromone another by an angular offset A. The angular offset A is preferablyone-half of the angular pitch B (e.g., 30 degrees). The first and secondsets of pulley teeth are preferably laterally offset by a rim 958.

In operation, the pulley teeth 952 preferably engage belt gaps 934disposed between belt teeth 936 to drive the conveyor 930 about thepulley 950. The belt gaps 934 are preferably spaced such that sequentialbelt gaps 934 along the conveyor 930 are alternatingly engaged by pulleyteeth 952-1 and 952-2. For example, in one embodiment the followingsteps may take place in chronological order during operation: a firstbelt gap 934 is engaged by a first pulley tooth of the pulley tooth set952-1, then a second belt gap 934 (e.g., the next belt gap following thefirst belt gap) is engaged by a first pulley tooth of the pulley toothset 952-2, then a third belt gap 934 (e.g., the next belt gap followingthe second belt gap) is engaged by a second pulley tooth of the pulleytooth set 952-1, then a fourth belt gap 934 (e.g., the next belt gapfollowing third belt gap) is engaged by a second pulley tooth of thepulley tooth set 952-2, and so-on. In operation, pulley gaps 954-1 and954-2 between the two sets of pulley teeth 952-1, 952-2 are similarlyalternatingly engaged (e.g., non-drivingly engaged) by belt teeth 936.In operation, the rim 958 is preferably partially received in alongitudinal slot (not shown) provided along the inner side of theconveyor 930 a laterally central position along the length of theconveyor. It should be appreciated that although the pattern of beltteeth 936 and belt gaps 934 are illustrated only along the right handside of the conveyor 930 (see FIG. 9), in preferred embodiments thispattern continues along the length of the conveyor.

FIG. 14 is a side elevation view of another embodiment of a seedconveyor 900A which is substantially the same as in the previousembodiment of the seed conveyor 900 shown in FIG. 9, except that in theembodiment of FIG. 14, the seed conveyor 900A utilizes a loading wheel910A having sinusoidal shaped fingers 911 as best shown in FIG. 15. Thesinusoidal shape of the fingers 911 allows for more compression of thefingers 911 when there are larger seeds thereby minimizing potentialclogging of the loading wheel 900A.

The foregoing disclosure is meant to be illustrative and is not intendedto be exhaustive or limited to the embodiments, systems and methodsdescribed herein. Many modifications and variations will be apparent tothose of ordinary skill in the art without departing from the teachingsprovided. It is intended that the foregoing disclosure, including theclaims, be interpreted to embrace all such variations and modifications.

The invention claimed is:
 1. A seed delivery apparatus, comprising: aseed meter configured to entrain seeds on a seed disc and to releasesaid entrained seeds at a seed release location; and a seed conveyorassembly having an upper end disposed to receive the released seed, saidseed conveyor assembly including: a housing; a seed conveyor having aninner surface and an outer surface, said inner surface having aplurality of inwardly projecting spaced teeth defining sequential beltgaps, said outer surface having a plurality of outwardly projectingspaced flights defining sequential flight gaps which receive thereleased seed; an upper pulley having a first set of radially arrangedpulley teeth and a second set of radially arranged pulley teethangularly offset from said first set of radially arranged pulley teeth,each of said first and second set of radially arranged pulley teethalternatingly engaging said sequential belt gaps; and a cleaning stripfixedly attached to said housing and disposed adjacent to said upperpulley to clean debris from said upper pulley; wherein said cleaningstrip extends arcuately forwardly along a direction of rotation of saidupper pulley.
 2. The seed delivery apparatus of claim 1, furthercomprising: an agitation strip disposed to agitate seeds conveyed bysaid conveyor.
 3. The seed delivery apparatus of claim 1, furthercomprising: a loading wheel disposed to introduce said released seedsinto said flight gaps of said conveyor.
 4. The seed delivery apparatusof claim 1 further comprising: a seed guide disposed to guide saidreleased seeds introduced by said loading wheel into said flight gaps ofsaid seed conveyor, wherein said seed guide includes a relief portionand an introduction portion.
 5. The seed delivery apparatus of claim 4,wherein said relief portion is disposed radially farther from the upperpulley than the introduction portion.
 6. The seed delivery apparatus ofclaim 4, wherein said relief portion extends arcuately along a pathsubstantially parallel to the path of said flights passing said reliefportion.
 7. The seed delivery apparatus of claim 4, wherein saidintroduction portion urges said seeds in a direction toward saidconveyor and into one of said flight gaps.
 8. The seed deliveryapparatus of claim 3, wherein said loading wheel comprises a pluralityof radial fingers.
 9. The seed delivery apparatus of claim 8, whereinsaid fingers have a sinusoidal configuration.
 10. The seed deliveryapparatus of claim 1, further comprising: a seed sensor configured todetect said entrained seeds before said seed release location.
 11. Aseed delivery apparatus comprising: a seed meter configured to entrainseeds on a seed disc and to release said entrained seeds at a seedrelease location; and a seed conveyor assembly having an upper enddisposed to receive the released seed, said seed conveyor assemblyincluding: a seed conveyor having an inner surface and an outer surface,said inner surface having a plurality of inwardly projecting spacedteeth defining sequential belt gaps, said outer surface having aplurality of outwardly projecting spaced flights defining sequentialflight gaps which receive the released seed; an upper pulley having afirst set of radially arranged pulley teeth and a second set of radiallyarranged pulley teeth angularly offset from said first set of radiallyarranged pulley teeth, each of said first and second set of radiallyarranged pulley teeth alternatingly engaging said sequential belt gaps;and a cleaning strip disposed adjacent to said upper pulley to cleandebris from said upper pulley, wherein said first set of pulley teethand said second set of pulley teeth are laterally offset by a rim. 12.The seed delivery apparatus of claim 11, wherein said inner surface ofsaid seed conveyor includes a slot which receives said rim.